1. Field of the Invention
The present invention relates generally to electrical circuits, and more particularly but not exclusively to circuit elements for digitally controlled oscillator fabricated as part of monolithic integrated circuits.
2. Description of the Background Art
In a digitally controlled oscillator, the operating frequency is adjusted by enabling or disabling a number of tuning circuit elements. The tuning circuit elements can be any components and circuits, such as transistors or varactors. In order to provide finer tuning resolutions and wider tuning ranges, a large number of tuning circuit elements are needed for adjusting frequencies.
The finer the resolution of the tuning circuit element is, the more the tuning circuit elements are needed in order to cover the same tuning ranges under voltage and temperature variations. To reduce area cost, an efficient access and storage scheme based on an array of memory cells are needed.